This invention relates to a package terminal air conditioning unit and, in particular to a split package terminal in which some of the air conditioning components are housed in an indoor cabinet of all molded construction and are connected to the remaining components housed in an outdoor cabinet by a pair of refrigerant exchange lines.
As described in U.S. Pat. No. 4,480,533 many package terminal units consist of a single self-standing cabinet that houses all of the component parts of an air conditioning system needed to heat or cool a specific zone or region within a building. The cabinet is typically situated next to an outdoor wall of the building and a rather large and unsightly air duct is passed through the wall so that sufficient outdoor air can be exchanged with the indoor air to satisfy the requirements of the unit. These ducts can structurally weaken the building, create unwanted loss of energy from the building and considerably alter the appearance of the building.
Most of today's package terminal units are housed in rather bulky metal cabinets in which heavy metal cover panels are mounted upon an equally heavy framework of metal support members. The heavy panels must be removed in order to gain access to the air conditioning components housed in the cabinet so that repairing and maintaining the unit can be a difficult and time consuming task. The metal panels can be easily dented or scratched through normal use. The metal parts of the cabinet are also exposed continually to moisture and refrigerants from the air conditioning unit which promotes rapid oxidation and rusting of these metal parts. As the rusting process progresses the parts or even the entire cabinet must be replaced which, of course, can be expensive.
The indoor air within the conditioned zone is drawn into the cabinet and passed over a heat exchanger before being discharged back into the zone. The duct work leading to and from the heat exchanger is usually formed of sheet metal. For the most part little or no consideration is given to the aerodynamics of the air moving pump or fan when designing the duct work. Consequently, the air handling characteristics of most metal cabinets are relatively poor and little can be done to improve the efficiency of the air flow through the system. Cabinets that have been specifically designed for use with a particular air conditioning unit must oftentimes be abandoned or considerably reworked when the unit is changed because the cabinet lacks flexibility to accommodate even minor changes in design.